Strange Problem with packets not getting back in open states

[bpr-admin]

Last week we changed from our old pfsense box to our new OPNsense box. All of the interfaces were configured identically. However yesterday we had to switch back.

We noticed lots of problems: DNS resolution was super slow, SSIS packages were not getting through (picture examples), smtp relaying not working. I will explain one of the issues below.

Scenario:
An MS-SQL server (209.xxx.xxx.152) sends data from an SSIS package to an AWS RDS instance.
Here's how that correctly looks in wireshark on the old pfsense box.



Here's how it looks on the OPNsense box, nothing outside of the server has changed:



Another odd thing is that the OPNsense box seems to be rewriting the packet to make it look like it's coming from itself.



Does anyone have insight as to what might be going on here? An additional detail is that we do not run NAT on this network.